Aerating apparatus



Jan. 28, 1964 F. J. CLARKE ETAL 3,119,339

AERATING' APPARATUS Filed Nov. 12, 1958 2 Sheets-Sheet 1 awn/r025 FRANK JOSEPH CLARKE, and THOMAS LESLIE GOLDSKITH 1964 F. J. CLARKE ETAL 3,119,339

AERATING' APPARATUS Filed Nov- 12, 1958 2 Sheets-Sheet 2 I A VEIV QS FRANK JOSEPH CLARE, and

THOMAS IESLIE GOLDSI-ZITI-I United States Patent C 3,11%,339 AERATENG APPARATUS Frank Joseph Clarke, urrey, and Thomas Leslie Goldsmith, London, England, assignors to Clarke-Built Limited, London, England, a company of Great Britain Filed Nov. 12, 1958, Ser. No. 773,355 2 Claims. (Ci. 103-6) The present invention relates to aerating apparatus which term is used to mean apparatus for injecting a gas into a liquid or semi-liquid and dispersing it in the liquid or semi-liquid and to the improved method of aerating. The gas may be a pure gas or vapour or a mixture of gases or vapours or both.

Such apparatus may be used for example, to carbonate or aerate beverages, to aerate ice cream, sweet confections, such as marshmallows and fondants, and creams and icings used in the confectionery and bakery industries or to condition plasticised latex, synthetic resins or other synthetic substances for the production of foam materials.

The invention is concerned with aerating apparatus of the type having an inlet pump connected in series with an outlet pump which is arranged, in operation, to pump at a faster rate than the inlet pump, a gas inlet being provided in the connection between the two pumps so that gas is drawn into and mixed with the liquid or semi-liquid pumped through the apparatus.

It is an object of the invention to provide a compact apparatus which enables greater turbulence to be set up in the region where the gas is drawn into the liquid than has heretofore been the case, and thereby to promote more efficient aeration.

According to the invention, aerating apparatus of the type specified comprises a housing enclosing adjacent pump chambers of the inlet and outlet pumps respectively, the chambers being interconnected by a transfer duct formed in the wall of the housing separating the two chambers, which housing is also formed with an inlet port opening into the inlet pump chamber for the admission of the liquid or semi-liquid, a gas inlet port opening into the transfer duct and provided with valve means for controlling the tlow of gas into the duct, and an outlet port opening into the outlet pump chamber for the discharge of aerated liquid or semi-liquid, the inlet pump chamber containing a coarse-toothed gear pump rotor adapted to draw the liquid or semi-liquid into the chamber and discharge it through the transfer duct to the outlet pump chamber and the outlet pump chamber containing a coarse-toothed gear pump rotor adapted to draw the liquid or semi-liquid from the inlet pump chamber, together with gas admitted through the valve, through the transfer duct into the outlet pump chamber and discharge it through the outlet port.

In order to fulfil the condition that, in operation, the pumping capacity of the discharge pump is greater than that of the inlet pum the pumps can be driven at the same speed if the discharge pump is larger than the inlet pump or the discharge pump can be driven at a greater speed than the inlet pump if this is not the case.

The inlet pump thus controls the rate at which the liquid or semi-liquid flows through the apparatus. The discharge pump creates a partial vacuum in the transfer duct which causes a flow of gas from the atmosphere, or from a gas supply source connected to the gas inlet port, into the transfer duct where it meets the liquid or semiliquid. Turbulence causes some mixing here and further mixing is effected in the discharge pump before the aerated liquid or semi-liquid is discharged through the outlet port. Because the pump chambers are adjacent, which gives a short transfer duct and because the coarse-toothed gear pumps give a pulsating flow, the flow in the transfer duct by way of example with reference to-the accompanying' drawings, in which:

FIG. 1 is a section through an aerating'appar atus,=

taken on the line 1-1 in FIG. 2, and

FIG. 2 is a section through the same apparatus taken on the line 11-11 in FIG. 1.

The aerating apparatus comprises a cast aluminium housing. The housing is in the form of a main body 10 and a front cover plate 11. Two cylindrical bores extend into the body ill from the front almost to the back, with their axes perpendicular to the front and back. These bores form the two pump chambers 16 and 17 of the apparatus and are covered by the front cover plate 11.

A channel or transfer duct 12 is formed in the metal wall 13 separating the two bores or chambers 16 and 17. The metal wall 13 is only of thickness comparable with that of the thinner portions of the external walls of the housing ltl. Accordingly the transfer duct 12 is short in relation to its width or transverse dimension and this promotes turbulence within the transfer duct. An aperture 14 in the body it opens into this transfer duct 12 and constitutes a gas inlet port. A gas inlet valve 49 is screwed into this port.

A mix or material or ingredient inlet port 15 formed in the side of the body 1th near the separating wall 13 and communi ates with the first chamber 16. The aerator unit outlet port 18 formed in the upper part of the body 1% communicates with the second chamber 17.

The cover plate 11 is clamped on to the body 10 in part by studs 20, but primarily by studs 21 which extend through to a cast bearing block 22 and also clamp this to the back of the body 1%. A main shaft 23 is journalled in two ball races 24 and 25 in the casting 22 and passes through a bushing 26 into the chamber 17. A ring gear 27 is keyed on to the end of the shaft 23 and meshes with a pinion 28 rotatably mounted inside the ring gear 27 on an eccentrically disposed stub shaft 29 fixed in the cover plate 11. A wall 36 of crescent section projects from the plate 11 in the space between the ring gear 2'7 and the pinion 28, opposite the point of engagement between these elements.

The gear 27, the pinion 28 and the wall 30 together form a gear pump for pumping and blending and discharging the aerated mix or ingredient or material and forcing the material round from the transfer duct 12 to the outlet port 18. Thus the ring gear 27 is driven round in the sense shown by the arrow 31 in FIG. 1, driving the pinion 28 in the same sense. Material, i.e. gas and mix or ingredient or material, is entrained in small slugs in pulselike fashion in the pockets formed between the wall 30 and the gears of the ring gear 27 and the pinion 28 and carried round the path indicated by the arrow 31 and the arrow St). The pockets are relatively large on account of the coarseness of tie teeth of the gear 27 and the pinion 28 and hence the flow from the pump is strongly pulsating, producing a mixing or very fine blending effect upon the mix or ingredient and gas being pumped.

A similar gear pump is arranged in the cavity 16 having a ring gear 32, a pinion 33 on a stub shaft 34 and a wall 35. The ring gear 32 is keyed on to a shaft 36 journalled in a ball bearing 37 in the casting 22 and passing through a bushing 38 in the body 1%.

The main shaft 23 carries a small pinion 39 meshing with a large pinion on the shaft 36. Accordingly the first stage or mix or ingredient gear pump in the cavity 16 is driven in the opposite sense to that of the pump in the cavity 17 and at a slower speed (approximately of the speed of the pump in the cavity 17). Material is thus driven round from the inlet port 15 to the transfer port 12 along the paths indicated by arrows 41 in FIG. 1, the

flow therein also being uneven and pulsating. The gas inlet port 14 is connected to a gas supply source through the gas inlet valve 49 or communicates with the atmosphere through the valve 49 when air is the gas used.

In operation, the material being aerated is pumped in the first chamber 16 and pumped out by the rotor in the second chamber 17, a partial vacuum being created in the transfer duct 12, by reason of the different speeds at which the pumps are driven. Gas is sucked in through the gas inlet port 14 and meets the irregularly and pulsating flow of liquid or semi-liquid sideways on. In the highly turbulent flow the gas is entrained intermediate the slugs or pulses of the liquid or semi-liquid, further dispersion of the mix or ingredient and gas occurring in the second chamber 17 before discharge of the well blended and aerated mixture through the outlet port 18. The gas inlet valve 49 is adjusted to provide the degree of aeration required. The degree of aeration is substantially constant for a given setting of the valve 49, being substantially independent of the rate at which the liquid or semi-liquid is pumped through the device.

Provision is made for adjusting the clearances of the ring gears 27 and 32 by motion of the shafts 23 and 36 along their axes. The mechanism for doing this will be described only with reference to the shaft 36. The thrust in the shaft 36 is towards the left in FIG. 2 and is transmitted to the bearing 37 by means of a collar 42 on the shaft. The bearing 37 is mounted in a collar 43 screwed into a threaded bore 44 in the casting 22. The collar 43 has a toothed outer periphery 45 meshing with a pinion 46 on a stud 47 journalled in the casting 22. The stud 47 has an end 48 of square section and may be rotated by a key applied to this end. By this means the collar 43 can be screwed into and out of the bore 44 and hence the clearance of the gear 32 be determined. It will be appreciated that these means for adjusting the pump clearances are such that adjustment can be effected whilst the pump is running.

In explanation of the manner of operation of the improved clearance adjustment feature of the pumps in the chambers 16 and 17, reference will be made, by way of example only, to such operation of the pump in chamber 16. The bearing 37, which is fixed in axial position on shaft 36 between collar 42 and a retaining ring (not numbered) is similarly fixed with respect to the bushing 43, which bushing, upon being rotated, advances or recedes axially in the casting 22, carrying with it the bearing 37 and the drive shaft 38. The inner end of the drive shaft 38 is socketed into the ring gear 32. When the pump is in operation, fluid pressure between the face of the ring gear 32 and the cover plate 11 will exert an axial thrust upon the ring gear 32 and will force the ring gear 32 against the inner end of the adjustable drive shaft 38, and such thrust is transmitted by shaft 38, by way of collar 42 and bearing 37, to the screw bushing 43. The idler gear 33, which is housed in a recess in the ring gear 32, floats on a stud shaft 34 and therefore adjusts its own clearance in response to adjustment of the ring gear 32.

The improved arrangement for adjustment of the ring gears of the pumps enables the mentioned clearances to be adjusted to particularly adapt the pumps for the handling of fluids of varying viscosity, and also provides a fine adjustment of the capacities of the pumps, whereby, if desired, some of the fluid being pumped may, upon making the necessary adjustment, be permitted to by-pass across the respective ring gear from the high pressure side to the low pressure side, and also provides means for compensating for normal Wear of the adjacent faces of the ring gears and the cover plate 11.

We claim:

1. An aerating device comprising, an inlet pump and an outlet pump and having housing means enclosing two 4 adjacent pump chambers for the two pumps respectively, said housing means including a thin wall portion posi-' tioned between said two adjacent pump chambers and separating said pump chambers, a transfer duct formed in said thin wall portion of said housing means between said pump chambers and interconnecting said pump chambers, said housing means being also formed with an inlet port opening into the chamber for the inlet pump for the admission of the liquid or semi-liquid to the pumped, a gas inlet port opening into said transfer duct and provided with valve means for controlling the flow of gas into said transfer duct, and an outlet port opening into the chamber for the outlet pump for the discharge of aerated liquid or semi-liquid, the chamber for the inlet pump c0ntaining a coarse-toothed gear pump rotor adapted to draw the liquid or semi-liquid into the chamber and discharge it in a continuous series of intermittent pulses through the transfer duct to the chamber for the outlet pump, the chamber for the outlet pump containing a coarse-toothed gear pump rotor adapted to receive the liquid or semi liquid from the chamber for the inlet pump and the gas from the gas inlet port through the transfer duct into the chamber for the outlet pump and discharge the blended mixture through the outlet port, both of the pump rotors being of the same construction and size and being driven by separate shaft means, gear means gearing together said shaft means, said gear means being of such relative sizes with respect to one another and being so arranged upon said shaft means that the pump rotor in the chamber for the inlet pump is driven at a lower speed than the pump rotor in the chamber for the outlet pump, each such shaft means being journaled separately in at least one thrust bearing whose axial location can be separately adjusted, whereby each of the shaft means can be separately adjusted axially and whereby the clearance of each of the respective pump rotors within said housing may be adjusted responsive to the axial adjustment of the associated shaft means.

2. A device according to claim 1, wherein the axiat location of each of said shaft means can be adjusted by rotation of a separate threaded member supporting the respective associated thrust bearing for the respective shaft means, each said threaded member having a toothed peripheral portion engaged by a pinion rotatable by means of a key, whereby adjustment of said clearance can be effected while the pump rotors are operating.

References Cited in the file of this patent UNITED STATES PATENTS 1,853,430 Jensen Apr. 12, 1932 1,877,688 Petersen Sept. 13, 1932 1,907,486 Boileau May 9, 1933 1,927,799 Mann Sept. 19, 1933 2,013,017 Vogt Sept. 3, 1935 2,208,273 Karasick July 16, 1940 2,406,964 Orr Sept. 3, 1946 2,483,705 Levetus et al. Oct. 4, 1949 2,593,369 Wachter Apr. 15, 1952 2,600,477 Burt June 17, 1952 2,615,399 Edwards Oct. 28, 1952 2,657,632 Kiefer Nov. 3, 1953 2,794,447 Spitz Tune 4, 1957 2,796,240 Miller June 18, 1957 2,845,867 Shoosrnith Aug. 5, 1958 2,881,800 Bauerlein Apr. 14, 1959 2,973,151 Zrolka Feb. 28, 1961 FOREIGN PATENTS 504,059 Great Britain Oct. 4, 1939 936,479 France July 24, 1948:

530,709 Belgium Aug. 14, 1954 531,356 Italy Aug. 1, 1955 

1. AN AERATING DEVICE COMPRISING, AN INLET PUMP AND AN OUTLET PUMP AND HAVING HOUSING MEANS ENCLOSING TWO ADJACENT PUMP CHAMBERS FOR THE TWO PUMPS RESPECTIVELY, SAID HOUSING MEANS INCLUDING A THIN WALL PORTION POSITIONED BETWEEN SAID TWO ADJACENT PUMP CHAMBERS AND SEPARATING SAID PUMP CHAMBERS, A TRANSFER DUCT FORMED IN SAID THIN WALL PORTION OF SAID HOUSING MEANS BETWEEN SAID PUMP CHAMBERS AND INTERCONNECTING SAID PUMP CHAMBERS, SAID HOUSING MEANS BEING ALSO FORMED WITH AN INLET PORT OPENING INTO THE CHAMBER FOR THE INLET PUMP FOR THE ADMISSION OF THE LIQUID OR SEMI-LIQUID TO THE PUMPED, A GAS INLET PORT OPENING INTO SAID TRANSFER DUCT AND PROVIDED WITH VALVE MEANS FOR CONTROLLING THE FLOW OF GAS INTO SAID TRANSFER DUCT, AND AN OUTLET PORT OPENING INTO THE CHAMBER FOR THE OUTLET PUMP FOR THE DISCHARGE OF AERATED LIQUID OR SEMI-LIQUID, THE CHAMBER FOR THE INLET PUMP CONTRAINING A COARSE-TOOTHED GEAR PUMP ROTOR ADAPTED TO DRAW THE LIQUID OR SEMI-LIQUID INTO THE CHAMBER AND DISCHARGE IT IN A CONTINUOUS SERIES OF INTERMITTENT PULSES THROUGH THE TRANSFER DUCT TO THE CHAMBER FOR THE OUTLET PUMP, THE CHAMBER FOR THE OUTLET PUMP CONTAINING A COARSE-TOOTHED GEAR PUMP ROTOR ADAPTED TO RECEIVE THE LIQUID OR SEMILIQUID FROM THE CHAMBER FOR THE INLET PUMP AND THE GAS FROM THE GAS INLET PORT THROUGH THE TRANSFER DUCT INTO THE CHAMBER FOR THE OUTLET PUMP AND DISCHARGE THE BLENDED MIXTURE THROUGH THE OUTLET PORT, BOTH OF THE PUMP ROTORS BEING OF THE SAME CONSTRUCTION AND SIZE AND BEING DRIVEN BY SEPARATE SHAFT MEANS, GEAR MEANS GEARING TOGETHER SAID SHAFT MEANS, SAID GEAR MEANS BEING OF SUCH RELATIVE SIZES WITH RESPECT TO ONE ANOTHER AND BEING SO ARRANGED UPON SAID SHAFT MEANS THAT THE PUMP ROTOR IN THE CHAMBER FOR THE INLET PUMP IS DRIVEN AT A LOWER SPEED THAN THE PUMP ROTOR IN THE CHAMBER FOR THE OUTLET PUMP, EACH SUCH SHAFT MEANS BEING JOURNALED SEPARATELY IN AT LEAST ONE THRUST BEARING WHOSE AXIAL LOCATION CAN BE SEPARATELY ADJUSTED, WHEREBY EACH OF THE SHAFT MEANS CAN BE SEPARATELY ADJUSTED AXIALLY AND WHEREBY THE CLEARANCE OF EACH OF THE RESPECTIVE PUMP ROTORS WITHIN SAID HOUSING MAY BE ADJUSTED RESPONSIVE TO THE AXIAL ADJUSTMENT OF THE ASSOCIATED SHAFT MEANS. 